Hello. I am self studying statistics and have become stuck on a question in the chapter on the Poisson distribution. Here it is:

A car hire firm has two cars which it hires out day by day. The number of demands for a car on each day is distributed as a Poisson distribution with a mean of 1.5.

And the question is:

What proportion of demands has to be refused?

Although it seems very simple I'm struggling to understand what the question is asking for. Any help you can give me would be gratefully received!

Thanks.